Device for evaluating cutaneous sensory detection

ABSTRACT

An improved hand-held device for evaluating cutaneous sensory detection consisting of a plastic or similar material rod handle and a simple curve that enables function and versatility not possible without the curve. The curve helps prevent an attached monofilament used as the testing stimulus from being laid down upon itself, or being damaged when put in a case. It helps prevent the monofilament from being sheared off by another device&#39;s handle when several devices are grouped for a cutaneous sensory detection test. One embodiment adds a disk attachment at the end of the handle curve and extension. The disk is pre-embedded with a monofilament of a given diameter size, and length, enabling the monofilaments to be quickly and easily replaced or interchanged by an examiner without replacing an entire device, or disassembling a device. Alternative disks contain two or a plurality of filaments of preselected diameter size and length. An optional connector for the handle, with or without the disk attachment, permits more than one device to be used together. The connector enables two of a selected monofilament size and force to concurrently or sequentially apply the given force of application. In the preferred embodiment, a light source is optionally attached to the rod handle, or handles. The curve and extension of the handle in the new device design enables the attached light source to transmit through the clear light-conducting handle, to be bent by the curve, and with or without the clear disk attachment, to illuminate the perpendicular monofilament test stimulus, its application tip, and a skin area of the subject tested.

FIELD OF INVENTION

The present invention relates to a testing device for the purpose ofperipheral nerve evaluation, in particular it relates to an improvedtesting device, more specifically it relates to a device used for thepurpose of testing patients for cutaneous sensory detection provided bythe peripheral nervous system, and central nervous system, in human oranimal subjects.

BACKGROUND OF INVENTION 1. IDS References and Publications

a) References Cited:

U.S. Patent Documents 2,704,539 Mar. 22, 1955 Fisher 3,074,395 Jan. 22,1963 Kevorkian 3,662,744 May 16, 1972 Low, et al 3,933,148 Jan. 20, 1978Wyler, et al 4,313,446 Feb. 2, 1982 Kanatani 4,823,806 Apr. 25, 1989Bajada 5,027,828 Jul. 2, 1991 Kovacevic, et al 7/860,900 Mar. 31, 1992Weinstein, et al 5,316,011 May 31, 1994 Weinstein, et al 5,381,806 Jan.17, 1995 Weinstein, et al 5,492,132 Feb. 20, 1996 Weinstein, et al5,823,969 Oct. 20, 1998 Christy 6,234,976 B1 May 22, 2001 Linden6,234,977 May 22, 2001 Christy 6,387,055 May 14, 2002 Christy

b) Other Publications Cited:

-   Bell, J A: Sensibility testing, In Hunter, J M; Schneider, L H;    Mackin, E J; and Bell, J A (eds), Rehabilitation of the Hand,    Philadelphia, C V Mosby:269-291, 1978.-   Bell-Krotoski, J A: Light touch-deep pressure testing using    Semmes-Weinstein Monofilaments, In Hunter et al (eds),    Rehabilitation of the Hand, Philadelphia, C. V. Mosby, 1990.-   Bell-Krotoski, J A: Pocket filaments and specifications for the    Semmes-Weinstein Monofilaments, J Hand Ther, Hanley & Belfus, 3:    26-30, 1990.-   Bell-Krotoski, J A; and Buford, W L, Jr.: The force/time    relationship of clinically used sensory testing instruments, Hanley    & Belfus, J Hand Ther, 1(2):76, 1988; Bell-Krotoski, JA; and Buford,    W L., Jr.: “The force/time relationship of clinically used sensory    testing instruments: A revision and update,” J of Hand Ther, 10(4):    297-309, 1997.-   Bell-Krotoski, J A; and Tomancik, E: The repeatability of testing    with Semmes-Weinstein Monofilaments; the American Society of Hand    Therapists; J Hand Surg, 12A, No 1, pp. 155-161, January 1987.-   Bell-Krotoski, J A; Fess, E E; Hiltz, D; and Figarola, J: Threshold    detection and Semmes Weinstein Monofilaments: A comparative study, J    Hand Ther, 8:155-162, 1995.-   Semmes, J; Weinstein, S; Ghent, L; and Teuber, HL: Somatosensory    Changes after Penetrating Wounds in Man, Harvard University Press    for the Commonwealth fund, Cambridge, 60-61, 1960. (Listed Library    of Congress)

Von Prince, K; and Butler, B: Measuring sensory function of the hand inperipheral nerve injuries, American J Occup Ther, 21:385-396, 1967.

-   Weinstein, S: Fifty years of somatosensory research: from the    Semmes-Weinstein Monofilaments to the Weinstein Enhanced Sensory    Test; J Hand Ther, Hanley & Belfus 6:11-22, 1993.

2. Discussion of Prior Art

a) Early Prior Art

Assessment of cutaneous sensory detection levels can allow mapping ofabnormal nerve areas and provide information on the condition ofperipheral nerves for the purpose of treatment or medical follow up, andis used in diagnosis of diseases and injuries. The sense of touch madepossible by our nervous system is our lifeline with the world outside ofour body. It provides us with the ability to discern objects. It helpsprotect skin and soft tissue from damage by providing quick recognitionof light touch and deep pressure detection. Cutaneous sensory thresholddetections is important in allowing us to “feel,” interpret objects, andprotect ourselves from harmful objects in the environment such asobjects with sharp edges and objects which could burn or otherwise causea wound. Sensitive repeatable measurement and quantification of earlyabnormality is important for early treatment intervention aimed atrestoring normal nerve function, or maintaining remaining nervefunction. Detection of more advanced abnormality is important to helpprevent injury and amputations. Quantification of nerve status inpatients is considered by some as critical. Without special care andtreatment, patients with peripheral nerve impairment who use hands andfeet in daily life activities can have repetitive damage to skin andsoft tissue resulting in injuries and amputations. In neurological andother examinations of patients with carpal tunnel or entrapmentsyndromes, work related injuries, repetitive stress syndromes,congenital neuropathies, and diseases such as diabetes and leprosy, itoften becomes necessary to locate, outline, and map skin areas of changeby testing cutaneous sensory detection in areas which are known to beinnervated by specific nerves.

A cutaneous sensory detection threshold test is not new and has beenaround since the 1800's. In body areas suspected of nerve change thetest was originally performed using horsehairs of increasing diameter.These were applied starting with the lightest until the subject detecteda force of application, i.e. cutaneous sensory detection level wasestablished. Devices using horsehair were apparently never patented.Horsehair has the disadvantage of absorbing humidity, thereby affectingthe force of application delivered to a patient. In addition, horsehairis fragile, sometimes brittle, and had to be replaced frequently.Horsehair is no longer used in cutaneous sensibility testing.

In the 1950's, Semmes and Weinstein replaced horsehairs used forcutaneous sensory testing with nylon monofilament of increasingdiameters placed in straight length plastic Lucite rod handles. Theoriginal Semmes-Weinstein device design uses a 6.35 mm square diameterclear plastic rod for a handle of a specified length into which a holeis drilled on one end of the rod to hold the nylon monofilament of thegiven size permanently attached at a 90-degree angle to the rod. Eachmonofilament is blunt cut to measures an exact 38 mm length from thepoint it leaves the rod handle. In order to assess the entire range ofpotential levels of cutaneous sensory detection—normal through abnormallevels—the lightest nylon monofilament size in the original complete setbegin at 0.0635 mm and progressively increase in diameter to a diameterof 1.143 mm. In the original Semmes-Weinstein Set of devices, 20monofilament sizes are available producing application force range from0.0045 gm to 447. gm. Each stimulus used in the test is applied 3 timeswith one out of 3 “yes” responses considered positive to establishdetection and recognition by a subject. The original instrumentincorporating the nylon monofilament was never patented, but has becomewidely used in cutaneous sensory testing of patients, it is a valuedtesting device by many examiners for cutaneous sensory testing, and isstill in use today. Semmes, J; Weinstein, S; Ghent, L; & Teuber, HL(1960) Somatosensory Changes after Penetrating Wounds in Man, HarvardUniversity Press for the Commonwealth fund, 60-61.

Nylon has little humidity absorption, has an indefinite shelf life, andrepeatable bend and recovery elastic physical properties making it idealfor the cutaneous sensory detection test. Nylon monofilament ofincreasing diameter size can provide a range of repeatable test stimuliapplication forces suitable for cutaneous sensory testing of individualsor groups of patients. When recorded for force of application recognizedby the subject, full or abbreviated versions of the test producedetailed and specific maps of peripheral nerve abnormality. Cutaneoussensory detection threshold levels were consistently color coded forspecific force recognition level in 1978, and provide information to theexaminer, physician, patient, family, employer, and judge regarding thestatus and change in nerve function. Bell, J A (1978) Sensibilitytesting, In Hunter, J M; Schneider, L H; Mackin, E J; & Bell, J A (eds),Rehabilitation of the Hand, Philadelphia, CV Mosby: 269-291.

Accuracy of the monofilament test for cutaneous sensory detectionthreshold is dependent both upon the properties of material being usedas a stimulus, and the proper application of the stimulus monofilamenttip for testing of subjects. Nylon monofilament, or material withsimilar physical properties, is applied perpendicular to the skinsurface of the subject until the monofilament bends and exerts itsdesired force of application for testing. The nylon monofilament bendswhen applied to the skin, achieves a peak force immediately inapplication, and holds peak force until lifted, when it again becomesstraight, and application force becomes zero. The force of applicationapplied by a device is important for test accuracy and validity.

A monofilament device has been shown to be more sensitive and accuratethan other hand-held instrument devices that use rigid plastic or metalin probe type instruments, that are not force-controlled in application.In studies of hand-held cutaneous sensory test devices, unless forceduring application is controlled for, even the vibration of theexaminer's hand has been shown to vary widely and can easily exceed thelighter application force needed for recognition of normal cutaneousthreshold detection. Unseen vibration, which is not easily appreciatedby an examiner's sight, will be detected by sensitive sensory end-organreceptors of the peripheral nerves in the skin of the patient beingtested, and can change the results of the test. The elastic propertiesof nylon help absorb the vibration of the examiner's hand. Normalsubjects are so sensitive they can feel light “puffs of air” on theirskin. The control enabled by the elasticity of the monofilaments canhelp quantify differences even among normal subjects at this sensitivelevel of detection. Bell-Krotoski, J A; & Buford, W L (1988, 1997) Theforce/time relationship of clinically used sensory testing instruments,Hanley & Belfus, J Hand Ther, 1(2):76; A Revision and Update,” J of HandTher, 10(4): 297-309.

The 90 degree angle of the monofilament to the rod handle, has beendetermined optimal. The angle enables smooth positioning when the deviceis in use, and helps to place the monofilament in the perpendicularposition to the skin area being tested, so that the stimulus applicationcan be made in a smooth and consistent fashion. The distance from themonofilament the examiner holds the handle should be consistent, as canalso make a difference on the amount of examiner hand vibration, and therepeatability of the stimulus. So long as the material is pure nylon, isextruded with controlled humidity in straight lengths on manufacture,diameter and length of the nylon monofilament are in specifications forsize and force, the stimulus is applied at a consistent distance fromthe examiner's hand, the monofilament is correctly cut without sharpedges, and the device is used in a correct application protocol, themonofilament test stimulus is highly repeatable from test to test, amongexaminers, and clinic to clinic. This means the handle holding themonofilament can be changed in design so long as the other knowncritical specifications are met and will still produce consistent teststimuli. Bell-Krotoski, J A; & Tomancik, E (1987) The repeatability oftesting with Semmes-Weinstein Monofilaments, J Hand Surg, 155-161.

Today the most frequently used variations of the monofilament cutaneoussensory detection test include a set of five or six devices with nylonmonofilaments consisting of specified diameter sizes, or a single deviceof a given size monofilament. Those included or used are the sizes mostneeded for patient testing from the original Semmes-Weinstein set of 20devices. Occasionally, examiners add additional monofilament sizes fromthe original set for specific needs in testing, such as for normativestudies where lighter than normal threshold stimuli are needed todetermine cutaneous sensory detection threshold in normal subjects.Bell-Krotoski, J A (1990) Light touch-deep pressure testing usingSemmes-Weinstein Monofilaments, In Hunter et al (eds), Rehabilitation ofthe Hand, Philadelphia, C. V. Mosby.

b) Disadvantages of Early Art and Attempt to Redesign

Disadvantages of the many Semmes-Weinstein design type sets with reducednumbers of monofilament are the same as with the original set of 20 inthat the monofilament can be damaged and need replacement. If only onemonofilament is broken in any set of increasing monofilament diameters,an entire test set can be rendered incomplete, e.g. where monofilamentsare used in a “hand and body,” “face,” or “foot” screen set, or in anerve status “screening” or “normative testing” set requiring more thanone monofilament size. Clinics doing testing often only have one set, ortwo sets available at any one time.

It is a common mistake for the examiner to inadvertently place theoriginal monofilament straight handle device on its side in a positionthat can damage the lighter monofilaments, or upside down on themonofilament, particularly when placed into its storage box. Whenopening boxed sets, persons not familiar with the monofilament designsuch as supervisors, custom inspectors, clinic visitors, etc., often donot know how to replace the monofilaments in correct orientation toprevent their damage. Persons curious about the device can and dounwittingly cause permanent damage, particularly to the lightermonofilaments. Many sets I have sent overseas have been received toodamaged to be useful by their intended clinicians because they wereopened in route and replaced incorrectly. Due to the high cost forreplacement and potential damage of the monofilaments in transit,alternative ways had to be found. In research grants on peripheral nervetesting, bulk packaged monofilament material was obtained and sentoverseas for placement into handles onsite within a country.

c) Pocket Monofilament Combined Handle Design

My earlier attempt to circumvent some of the recognized disadvantages ofthe original Semmes-Weinstein device resulted in the creation of a“pocket set” device design that put the then most commonly usedmonofilaments into one metal handle device with square metal rod arminterlocking extensions that could be expanded or collapsed for patienttesting. Bell-Krotoski, J A (1990) Pocket filaments and specificationsfor the Semmes-Weinstein Monofilaments, J Hand Ther, Hanley & Belfus,January-March, 26-30. This design was published but never patented, andis no longer in use. The nylon monofilament material in this device wasmade in color during manufacture, for diameter size and applicationforce for the monofilaments most frequently used in hand/foot/or bodytesting. The coding was made to correspond with consistent color-codingfor cutaneous sensory detection levels I introduced in 1978, for mappingabnormal peripheral nerve areas. Bell, J A (1978) Sensibility testing,In Hunter, J M; Schneider, L H; Mackin, E J; & Bell, J A (eds),Rehabilitation of the Hand, Philadelphia, CV Mosby: 269-291. Theaddition of color for identification of monofilament diameter sizeinsures correct recognition by the examiner of a given diameter sizemonofilament in a device, facilitates several monofilament sizes beingable to be put into one handle, and is frequently used in variousversion of the monofilaments test today.

Disadvantages of the “pocket set” included that the 1.5875 mm and 2.38mm square diameter handles in this thin metal multiple monofilamentcomposite handle design, still leaves the monofilaments vulnerable whileextended or collapsed during patient testing, in relation to theexaminer holding the handle. Replacement of one monofilament requiresreplacement of the entire instrument device including handle, or part ofthe handle and its specified diameter size monofilament. Since handleparts are not uniform in design, replacement parts are not practical forreplacement of only one. Additional monofilament sizes when needed arenot available that are frequently used in the testing set asalternative, except individually. Even with color, the stimulusapplication of the tip of the smallest monofilaments to the skin surfaceof a patient remains hard for some examiners to see, particularly in lowlight conditions.

d) Different Monofilament Stimulus Tip

Weinstein, et al, in U.S. Pat. No. 7,860,900, Mar. 31, 1992, introduceda specific treatment to the monofilament stimulus tip to produce arounded tip for measuring itch sensitivity. Weinstein describes theinadvertent elicitation of pain rather than touch or pressure to be aproblem in use of the original Semmes-Weinstein instrument. If theoriginal Semmes-Weinstein monofilaments are applied to the eye or mucousmembranes as described, and included in their testing, the monofilamenttest could produce pain. The modification of the monofilament tip tomake it curved and rounded may have advantages over the original design,but creates a different device instrument.

The test stimulus has been changed when the stimulus tip is rounded.This means that information developed in normative studies and forpatients with impairment, using the original blunt cut Semmes-Weinsteinstimulus, does not directly apply to the device design with rounded tipsand vice versa Bell-Krotoski J A, Fess E E, Hiltz D, & Figarola J:Threshold Detection and Semmes Weinstein Monofilaments: A ComparativeStudy, J Hand Ther, 8:155-162, 1995.

If blunt cut as in the original design, and not containing sharp edgesby incorrect cut on manufacture, the monofilaments in the original setof 20 monofilament diameter sizes rarely elicit a pain response inpatients who are being tested for normal and abnormal peripheral nervefunction of skin areas of the face, body, and extremities. Evenhypersensitive patients tolerate the test well. In these patients andothers with higher spinal cord, head trauma, or abnormality causingsensory changes to the head, body, and extremities, the test stimulusneeds to be in the range of light touch to deep pressure for cutaneoussensory detection as provided by the original Semmes-Weinstein design.The original monofilament cutaneous sensory detection blunt cutmonofilament device design remains valid and valuable in patienttesting.

If patients with nerve abnormality do not feel the heaviestmonofilament, they may still have residual pain response intact, butthis is tested by a different type of device. Pain is produced at muchhigher force levels than produced by the monofilaments, and test devicesspecifically for pain require sharp tipped instruments that can reachhigher force/pressure levels on the subject skin tissue such as the manypin or pinwheel type devices. Kavorkian, U.S. Pat. No. 3,074,395, 1963,invented a pinwheel algesimeter, and others such as Bajada, U.S. Pat.No. 4,823,806, Apr. 25, 1989, invented one of many variations of pin orpinwheel design instruments for testing pain detection of the sensorysystem. Disadvantages of these include that while these may be suitablefor testing pain, as intended, since they are a relatively heavystimulus, they lack the specificity, and the sensitivity needed fortesting lighter levels of cutaneous sensory detection important forearly detection of nerve abnormality, early intervention, andquantification of change.

e) Weinstein Combined Handle Design

Based on the criticisms of the original Semmes-Weinstein device design,and my described monofilament “pocket set,” Weinstein introduced acombined handle design incorporating the most used monofilament sizesinto one handle for measuring itch or pressure sensation, Weinstein, et.al, U.S. Pat. No. 5,316,001, May 31, 1994. In trade this invention isreferred to as the Weinstein Enhanced Sensory Test (WEST). Weinstein, S(1993) Fifty years of somatosensory research: from the Semmes-WeinsteinMonofilaments to the Weinstein Enhanced Sensory Test; J Hand Ther,Hanley & Belfus 6:11-22. The WEST has monofilaments that rotate outwardfrom one handle to be individually placed in the position for testing at90 degrees from the device handle, and returned to an array arrangementwith the other monofilaments. This device design has some advantage ofmaking the test more convenient, and better protects the monofilamentsif the instrument is dropped. The device design places the largestmonofilament in the array of several on the forward end of the handle,the largest monofilament and handle thereby protecting the lightermonofilaments when in its stored position. In a later invention usingthe WEST, Weinstein, et al, in U.S. Pat. No. 5,381,806, Jan. 17, 1995,added a method of delivering pressure-induced sensations for itchsensitivity of the skin surface of a subject by dragging themonofilament distally and proximally across the skin surface. In afurther improvement of the WEST device, Weinstein specifically obtaineda patent for the monofilament tip treatment that makes it curved androunded thus reportedly eliminating eliciting a pain response, andhelping to prevent slippage and misapplication of a monofilament to thepatient's skin, Weinstein, et al, U.S. Pat. No. 5,492,132, Feb. 20,1996.

Disadvantages of the WEST design include the fact that the more themonofilament is manipulated during use in the handle (rotated for use),the more likely it can be damaged, particularly if incorrectlyapproached by the examiner's hand rotating the selected testmonofilament away from the others included on the handle. Themonofilaments in the WEST design, affixed in a certain array arrangementof monofilament sizes in one handle, are not protected by the handledesign when rotated in position for use. The handle has to bedisassembled for repair or replacement of the monofilament. Since themonofilaments are lined up at various distances from the handle, thereis no provision for the monofilament to be applied at the same distancefrom the examiner's hand during application of the device.

All versions of the WEST have a different monofilament stimulus tip thanthe original blunt cut design Semmes-Weinstein monofilaments which werenever patented. Information developed in normative studies and forpatients with impairment, using the original blunt cut Semmes-Weinsteinstimulus, does not directly apply to the device design with rounded tipsand vice versa. Bell-Krotoski J A, Fess E E, Hiltz D, & Figarola J:Threshold Detection and Semmes Weinstein Monofilaments: A ComparativeStudy, J Hand Ther, 8:155-162, 1995.

f) Later Variations

Christie, U.S. Pat No. 5,823,969, Oct. 20, 1998, introduced a newhand-held device handle with nylon monofilament in pivoting head, wherethe monofilament incorporated into the head rotates from a channel inthe pen handle to a 90 degree angle for testing, and then is rotatedback to the channel in the pen for storage, thus protecting themonofilament when not used. An advantage is that the pen type devices,when in stored position, can be placed adjacent to each other in a caseor small packet without damage, with several of specified sizesincluded.

Disadvantages of the Christie device include the fact that the more themonofilament is handled or manipulated in a handle, the more likely itis to be damaged. The head that rotates out of a channel with themonofilament and away from the handle during patient testing can becomeinadvertently damaged by the examiner's hand when rotating themonofilament into its test position. The monofilament in this device isfully protected only when stored in the channel in the handle, not whileextended out of its handle 90 degrees, for patient testing. Replacementof the monofilament is accomplished by replacing the whole pen typedevice of a given size monofilament. The device heads with fixed givensize monofilament are not designed to be routinely interchanged on otherhandles for other size monofilaments by the examiner.

Linden, U.S. Pat. No. 6,234,976 B1, May, 22, 2001, introduced ahand-held device handle design with a rotating head and nylonmonofilament on the forward end of a device handle for measuring“protective sensation” (protective sensation being a previouslydescribed threshold detection level of many significant levels ofcutaneous sensory function). Von Prince, K; & Butler, B (1968) Measuringsensory function of the hand in peripheral nerve injuries, American JOccup Ther, 21:385-396. The monofilament in this device is fullyprotected only when stored in its protective channel in the handle, notwhile extended out of its handle 90 degrees, perpendicular to thehandle, for patient testing.

In recent years individual monofilaments, primarily intended to measurea level of “protective sensation” for testing of the diabetic foot, havebecome available in disposable flat paper holders. These are intendedfor one or limited-time patient screen testing, not for clinical testingwhere accuracy is paramount. Disadvantages include that the paper doesnot firmly secure a monofilament where it is attached. Another versioncan be found in small relatively flat plastic handles with themonofilament extending straight out from the handle. The paper orplastic versions (no patent found) do not incorporate the desired lengthof handle or 90 degree orientation of the monofilament with respect tothe handle, considered by experts to help dampen the normal vibration ofthe examiner's hand in patient testing. No provision is made forapplying the monofilament test stimulus at a given distance from theexaminer's hand. On a practical level, without touching an area of thepatient's hand during testing, the handles are too short to alwayspositioning the monofilament perpendicular to the patient skin areatested, particularly when applying the monofilaments to the hand inclinical testing.

g) Other Related Art

Low et al, U.S. Pat. No. 3,662,774, May 16, 1972, provides a variationin a hand-held device design for cutaneous sensory testing. This deviceuses one single vertical handle and a single nylon monofilament thatextends and retracts in the vertical handle to deliver a range ofapproximate forces of application. This device design does not allow thesame control of the examiner's hand vibration, as do designs that holdthe monofilament perpendicular to the handle. Further, the device handleconstantly crimps the Nylon monofilament along its length duringadjustments, causing early fatigue of the monofilament material andquickly causes mechanical damage to the monofilament where it iscrimped. The monofilament is not replaceable except in another device,or by ordering another monofilament assembly if available separately.Christie, U.S. Pat. No. 6,234,977. May 22, 2001, introduced a similarretracting and extending monofilament design, which has the samecriticisms.

Two- versus one-point stimulus testing is a common test variation incutaneous sensibility testing. Conventionally, the test is performedwith metal probe type devices. Several hand held devices have beendesigned for testing one- and two-point discrimination of the hand incutaneous sensory testing, e.g., Christie, U.S. Pat. No. 6,387,055, May14, 2002. These devices while historically popular and advocated inclinical use by many, they lack force control, similar to otherhand-held tests that have been found to lack sufficient control on theirforce of application needed to be a repeatable stimulus. Their force ofapplication has been shown to vary widely from one application toanother and one test to another. There is also no control on the forcethat can be added by the examiner. Applied force can vary as much as 30grams from one application to another, and range from 2 grams to overseveral hundred grams. Two-point testing devices have been foundadditionally variable in that they consistently produce a heavier forcewhen one point is applied versus when two points are applied, or viceversa, clearly showing the need for control on force applied.

Kovacevic, et al, U.S. Pat. No. 5,027,828, Jul. 2, 1991, provides acomputerized stimulus device for determining the sensory responses ofthe human skin primarily to evaluate the ability to discriminate one ortwo points of touch on the hand, but the device can be applied with onlyone point in contact with the skin for cutaneous sensory detectionthreshold testing. Force/pressure detection is recorded when the subjectclicks a signaling device indicating recognition. Although computerized,this device is typically hand applied. This device is a differentinstrument from the devices that use monofilament. When applied, lightcontact is made, and the force is ramped up to the level at which thepatient detects stimulation. The probes do not bend, but the device issaid to have electronic sensors for determining displacement of forcethat helps dampen the vibration of the examiner's hand duringapplication. Disadvantages of the device include that the testapplication probes are hand-applied, made of metal, and can conducttemperature. Rather than respond, “yes” to a specific thresholdstimulus, as in the monofilament test, the patient must determine whenthey begin to detect a stimulus that is already in skin contact, andclick a control. If they delay even a second to be sure they haveactually felt a stimulus, a heavier threshold can be recorded.

Kanatani, U.S. Pat. No. 4,313,445, Feb. 2, 1982, introduced a hand heldsteel wire aesthesiometer as another variation in cutaneous sensibilitytesting. A steel wire in this device bends in a length along ahorizontal plane rather than a vertical axis as do the monofilaments.There are other important differences in application of this instrument.Similar to the computerized metal instrument, when the device isapplied, light contact is made, and the force is ramped up to the levelat which a patient detects stimulation. Disadvantages include that wireis malleable, and can become bent with repeated application, reducingthe intended force of application. With the metal being relativelyrigid, the vibration of the examiner's hand can be exaggerated intransmission to the subject rather than absorbed or dampened.

In other more loosely related instruments designs Fisher, U.S. Pat. No.2,704,539, Mar. 22, 1955, provides hand-held design for a spring-loadedpin for sensory detection. Wyler, et al, U.S. Pat. No. 3,933,148, Jan.20, 1976, provides a hand-held spring-loaded device design fordetermining skin reactive sensitivity on the basis of a persistent skinstreak. Disadvantages include that springs are notoriously hard tocalibrate exactly, and a needle or pin, as stated previously, producetoo heavy stimulus force to apply the sensitive detection thresholdsneeded for cutaneous sensory testing.

3. Overall Disadvantages of Prior Art

It is a significant problem to the examiner when the device that needsto be used in a clinical test becomes damaged. An examiner may have onlyone damaged device of a needed size available in the set of several.Examiners may continue to use the damaged, less than accurate, set ofdevices, or not perform the needed exam. Clinicians are more likely toreplace questionable monofilaments used as test stimuli if they areeasily interchanged.

-   -   a) Monofilament is fragile: The monofilament in the original        Semmes-Weinstein device handle design is most fragile where it        leaves the rod. Here it can be inadvertently bent at a severe        angle, potentially changing its force of application as the        testing stimulus and accuracy when applied to the patient. A        monofilament, particularly the lightest used for testing of        normal subjects, can break or come out at the point where it        leaves the rod handle.    -   b) Handle sides are often confused: In the original        Semmes-Weinstein device design that uses the straight clear        square plastic rod handle, the side into which a hole has been        drilled for housing the monofilament looks exactly the same as        the other sides of the device. The very small monofilament        “hairs” can be easily damaged if the rod handle is inadvertently        laid down upon the monofilament, or if the monofilament is laid        down upon itself, particularly if a storage case is dropped and        the monofilament devices fall out.    -   c) Adjacent handle damage to monofilament: In the        Semmes-Weinstein original straight handle device design, if two        or more devices are assembled together, or nested, the end of a        neighboring adjacent rod handle can shear off the monofilament        of another. This happens when two or more devices are grouped        for using several different diameter monofilaments sizes        together for the specific test.    -   d) Large box needed for protective storage: In the original        Semmes-Weinstein device design the devices cannot be nested,        thus they require a relatively large box container, which can be        cumbersome, whereas clinicians prefer devices that can fit into        a pocket. Large boxes cannot fit easily on or near a treatment        table or area, and are more apt to be knocked off of the table        when other therapy or testing equipment is used, thereby        damaging the monofilament devices.    -   e) Unmet need for currently applying more than one device: It        has been clearly demonstrated that hand-held instruments for        performing the two-point discrimination version of cutaneous        sensory tests do not adequately control force of application        applied by the examiner. Yet many examiners maintain that a        two-point stimulus application versus a one-point is superior to        the monofilament cutaneous sensory threshold test. Thus there is        a need for more than one repeatable stimulus force of        application in cutaneous sensory testing, if for no other reason        than to determine the difference in variations of the cutaneous        sensory tests.    -   f) Unmet need for consistent holding of handle: When applying        the original device design Semmes-Weinstein Monofilament to the        subject, examiners hold the rod handles in inconsistent ways.        Some choke up on the monofilament, some place their index finger        on the opposite side of the handle directly over the        monofilament, and some—correctly—hold the instrument by placing        their index and other fingers at a given distance from the        monofilament during every patient application.    -   g) Fixed monofilament in handle: The monofilament in the        original straight handle Semmes-Weinstein device design is        permanently fixed to the rod handle, thus if damaged, the whole        unit device has to be replaced with an entirely new rod handle        and monofilament. This is costly, and time consuming to reorder,        as well as interruption to patient testing. Often clinicians        only have one set available for testing. Replacement        monofilaments are not available for the original device except        by replacing the entire device containing a specific        monofilament size. All the original Semmes-Weinstein design set        of 20 devices and various reduced number of monofilament sets        using the original Semmes-Weinstein design, share this in        common. Other device designs assembling selected size        monofilaments, with or without a single handle, share the same        problem of not being easily interchangeable without replacing        the entire device or being disassembled.    -   h) Unmet need for disposable or replaceable monofilament: That        the monofilament in the original straight handle        Semmes-Weinstein design is permanently fixed to the rod handle,        makes the use of disposable monofilaments prohibitive in cost,        as the device has to be replaced. While the monofilament can be        cleaned, it is not usually sterilized between patient test        applications. The device can be cleaned by dipping a        monofilament tip in hydrogen peroxide, etc., but is not usually        between patient test applications. Disposable devices are        important for health safety in patients with resistive diseases        such as TB and HIV.    -   i) Unmet need for other test stimulus variations: That the        monofilament in the original straight handle Semmes-Weinstein        device design is permanently fixed to the rod handle, limits        alternative stimuli for cutaneous sensory testing, the        monofilaments can apply.    -   j) Stimulus application needs to be repeatable for accuracy:        Examiners need to assure that the monofilaments are applied        perpendicularly to the skin area tested in order for the        monofilaments to exert intended force of application or they        will apply too little force. They can slip across the skin        surface and be misapplied. The subject could be judged not to        have detected the monofilament force of the specific cutaneous        threshold when, instead, the examiner has misapplied the        monofilament. If applied at an angle, they are likely to slip.        Misapplications can easily be disregarded and not recorded if        recognized by the examiner, but if unseen and unrecognized are        incorrectly reported.    -   k) Unmet need for stimulus application to be visual: It is        commonly understood that the monofilament test needs to be        performed in a well-lighted area, but this is not always        possible in clinic, field, or emergency room situations. The        monofilaments in the original Semmes-Weinstein device design are        clear and it is hard for the examiner to see and monitor correct        application of the tip, particularly of the lightest        monofilament sizes, during patient testing. Monofilaments with        color stains (pigments can change properties) are sometimes        available in those sizes most frequently used, but even with        color it is hard to see the lightest monofilaments under some        conditions.    -   l) Light is essential for testing in low light conditions:        Examiners often resort to using a lamp over the skin area being        tested, but direct light can elevate the skin temperature of the        area being tested by several degrees F. It is generally        desirable to measure and maintain the ambient temperature of the        room at a constant level during testing and repeat testing, as        it is known that nerves conduct faster when warmer than when        cold, and heating the monofilament several degrees, can change        its degree of stiffness and therefore accuracy of intended force        of application.    -   m) Imperative need for safe and accurate testing: Patients with        nerve injuries from trauma such as severed and replanted parts        and extremities, spinal cord injuries, or surgical repairs of        nerves, often have fragile medical conditions. Subjects are        sometimes tested or monitored at night or at times the tissue        and the patient need to be as little disturbed as possible. It        stands to reason that the test stimulus needs to be applied as        carefully and precisely as possible, particularly avoiding areas        of wounds or sutures.

New Device 1. Objects and Advantages of New Device

Accordingly, several objects and advantages of my invention are . . . .

-   -   a) (Monofilament is better protected from damage) to provide a        handle design in the my new device that can reduce the risk of        monofilament damage during use in a simple device design, and at        the same time make the instrument more functional and versatile.    -   b) (Monofilament side of handle is made obvious) to provide a        handle design in my new device in which the handle side where        the monofilament is attached is clearly obvious.    -   c) (Monofilament protection from adjacent handle damage enabled)        to provide an improved handle design in my new device where        several monofilaments can be safely assembled together,        reassembled, and disassembled for various cutaneous sensory        tests.    -   d) (Small box or case is enabled) to provide an improved handle        design in the new device where several monofilaments desired for        a specific test can be safely assembled, and nested storage in a        small box or case.    -   e) (Option for application of two or more devices is enabled) to        provide a means for attaching two or more devices for concurrent        stimulation with preselected force of application.    -   f) (Consistent holding of handle enabled) to provide, in the        preferred embodiment, a mark or rest for the examiner's index        finger, on the side opposite the monofilament, at a given        distance from the monofilament to enable consistency in examiner        holding and applying the device.    -   g) (Replaceable monofilament members enabled) to provide        monofilament replacement disks in the new device where a damaged        monofilament can be quickly and easily replaced.    -   h) (Disposable or replaceable monofilament members enabled) to        provide economical monofilament replacement disks in the new        device where an unclean monofilament can be quickly and easily        replaced.    -   i) (Option for other test stimulus variations enabled) to        provide alternative monofilament replacement disks in my new        device that can be interchanged with other discs for additional        or alternative stimuli.    -   j) (Repeatable stimulus application enhanced) to minimize        slippage and twisting of the monofilament during application to        the patient in the new device by assuring correct application of        the monofilament stimulus.    -   k) (Visual monofilament member enabled) to provide for the        monofilament in my new device to be as visual as needed and        optimally used in the variety of clinic and field situations by        assuring the monofilament and its tip are visible to the        examiner at all times.    -   l) (Option for light enabled when needed) to provide for        transmission of indirect or cool light through the handle and        over the test stimulus, the monofilament member, and, in the        preferred embodiment, the clear disk containing the        monofilament, thereby illuminating the monofilament during        testing.    -   m) (Improvement in safe and accurate testing) to provide for        adequate but non-glare light to illuminate the skin area of the        subject tested, particularly in low light and at night for        patient monitoring.

Further objects and advantages of my new device will become apparentfrom consideration of the drawings and ensuing description.

2. Summary of Invention

What is needed to improve cutaneous sensory threshold testing but notavailable in previous art is a versatile handle for a visiblemonofilament stimulus whereby several diameter sizes can be groupedsafely together and be readily available for clinical testing by anexaminer in a small box or packet, with replacement monofilaments onhand and readily interchangeable as needed to assure a test is accurate,safe, and more versatile for clinical use in patients, or research intovariations of optimal sensory test design. Weinstein and others havecreated usable instrument devices with several types of handles fortesting cutaneous sensory detection threshold in prior use, but it isproposed that the best solution is to resolve the disadvantages of theoriginal device and create a simple but improved device handle designthat can help protect the monofilament test stimulus with as few movingparts as possible, and provide for the versatility needed when thedevice is used in patient testing.

My new device design for cutaneous sensory detection testing includes afunctional handle, means for replaceable monofilament, and option for alighted monofilament stimulus whereby several devices of same ordifferent diameter sizes can be safely grouped together and be readilyavailable for clinical testing by the examiner in a small box or packet.Replacement monofilaments can be on hand and readily interchangeableduring testing as needed to assure the test is both accurate and safefor clinical use in patients. The addition of the curve and extension tothe handle better protects the monofilament where it is attached to thehandle. If inadvertently laid down incorrectly the handle falls on itsside or back, not on the monofilament. If dropped, the device lands onits back or side rather than the side to which the monofilament issecured. The curve and extension in handle design helps prevent thehandle from being laid down on the monofilament, and the monofilamentfrom being laid down upon itself and damaged. The curve serves thepurpose of letting the examiner immediately recognize the correctorientation of the handle. The curve and extension in handle designprevents one device when grouped or nested together from shearing offits neighbor monofilament, with or without a replaceable diskattachment. The replaceable disk serves as an additional cushion andshield for the monofilament, and fits into the handle curve andextension of a neighboring device when assembled. Monofilament devicesin the new design can be secured in the smaller box or case forcoat-pocket, tabletop, or other form of display, and are safer if thebox is dropped.

3. List of Names

a) Prior Art:

-   7. Straight rod handle device design (prior art)-   9. Monofilament member (prior art)-   11. Point monofilament member exits from straight rod handle and is    most vulnerable to damage (prior art)-   13 Monofilament end of straight rod handle that can damage a    neighboring monofilament when assembled together (prior art)

b) New Device:

-   15. Device handle-   17. Functional curve-   19. Handle curve extension-   21. Monofilament member-   23. Monofilament stimulus tip end-   25. Monofilament embedded in handle end-   27. Hole in handle for monofilament-   29. Mark or rest for examiner index finger to consistently hold the    device.-   31. Adapter connector for two handles-   33. Disk attachment with monofilament for replacement or interchange-   35. Example of alternative disk attachment for two point testing-   37. Example of alternative disk attachment for three point testing-   39. Alternative attachment means of clip for the disk replacements    or interchange-   41. Hole for clip attachment to hold disks-   43. Adaptor attachment for handle connection to a known    light-emitting source-   45. Hole in adaptor to fit handle-   47. Hole in adaptor to fit light source-   49. Known light-emitting source (circled L)-   51. Known battery generated light source-   53. Lighted skin area and test site

4 Brief Description of the Drawings

a) Prior Art:

FIG. 1A shows in prior art a Semmes-Weinstein monofilament style rodhandle device design, monofilament, and its point of exit from thestraight handle rod where it is most vulnerable to damage.

FIG. 1B shows in prior art a view of what happens when the handle islaid down on the fixed monofilament and damaged.

FIG. 1C shows in prior art how the end of an adjacent handle can shearoff and damage a neighboring monofilament by hyperflexion of themonofilament at its attachment where it exits the rod.

b) New Device:

FIG. 2A shows my new device handle incorporating a functional protectivecurve, and extension containing nylon monofilament in one embodiment,and the preferred embodiment of a mark or rest on the handle oppositethe side of the monofilament for consistent placement of the examiner'sindex finger on the handle, at a distance from the monofilament.

FIG. 2B shows several of the new devices nested together without injuryto the monofilament using the new handle design, one curve abuts anotherhandle curve, not the monofilament.

FIG. 3A shows two new device handles and optional connector attachmentin one embodiment, for two or more device handles to be secured togetherduring patient testing.

FIG. 3B shows a close up of one embodiment of the connector attachmentfor two handles.

FIG. 4A shows the new device in the preferred embodiment, adding to thenew handle a replacement disk fitted to the terminal end of the handlecurve and extension, the disk having been pre-embedded with themonofilament of preselected diameter size.

FIG. 4B shows two examples of a variety of possible alternativereplacement disks to enable two or more concurrent monofilament membertest stimuli.

FIG. 4C shows the new device with embodiment incorporating analternative means for securing the replaceable disk at the terminal endof the handle curve, the disks sliding into and out of position, andsecured with a clip, the clip fitting into a hole drilled into theplastic handle at the terminal end of its curve and extension.

FIG. 4D shows a close up of an example of the alternative clipembodiment to secure the disk at the terminal end of the handle curve.

FIG. 4E shows that when several of my new device handles are assembledtogether with disk attachments, the disks abut an adjacent handle curveand extension, not the monofilament, and the handles can be safelynested together without damage to the monofilament.

FIG. 5A shows an example of an adaptor attachment and a light source fora cutaneous sensory detection device. Either the handle in claim 1, orhandle with addition of disk attachment in claim 2, can be connected andused by the adaptor and light-emitting source, or alternative cutaneoussensory testing device handle.

FIG. 5B shows in the preferred embodiment the assembly of my new device,with removable or replaceable disk and embedded monofilament, asattached to the terminal end of the curve extension of the new handle,handle, mark on the handle for the examiner's index finger to hold thedevice, and adaptor attachment for a small conventional battery poweredlight from the group of available light sources.

FIG. 6 shows my new device with preferred embodiment of a light-emittingsource, clear attachment connector, clear handle, clear disk, andtransmission of light to, or illumination of, the monofilament, themonofilament stimulus tip, and skin area of the subject, or site beingtested.

5. Detailed Description of Drawings

The preferred embodiment of my new device can best be seen by viewingFIGS. 4A, and 5B.

a) Prior Art:

FIG. 1A shows a prior art Semmes-Weinstein monofilament style devicestraight rod handle design 7 attached monofilament 9 and its point ofexit from the straight handle rod 11 where the monofilament is mostvulnerable to damage on a forward monofilament end of the handle 13.

FIG. 1B shows in prior art a view of what happens when the forwardmonofilament end of the handle 13 is inadvertently laid down on thefixed monofilament 9 and damaged.

FIG. 1C shows in prior art how the forward end of an adjacent handle 13can damage a neighboring monofilament 9 when several devices areassembled together for test or case.

b) New Device:

FIG. 2A shows my new device handle 15 incorporating a functional curve17 and an extension 19 of the handle to help protect a monofilament 21having on one end a stimulating tip 23 and, in one embodiment, the otherend 25 embedded in the handle curve extension 19. The monofilament isglued into a hole 27 in the handle securing the monofilament in aperpendicular orientation to the length of the handle. This drawingillustrates how the curve addition to the handle helps to protect themonofilament where it is attached to the handle. When laid down ordropped the new device handle is more likely to fall on the handle sidewithout the monofilament test stimulus, not on the monofilament where itexits the handle. The curve 17 serves the purpose of letting theexaminer immediately recognize the correct orientation of the handle.Also shown is the preferred embodiment of an identifying mark 29 thathelps to further improve recognition of the correct orientation of themonofilament. It also provides a specific point for the examiner's indexfinger to contact the handle and hold the device on the first end of thehandle for application at a consistent distance from the monofilament onthe forward second end. Not only does the mark help protect themonofilament from damage from the hand of a novice examiner, it servesto help insure smooth application with minimal vibration of theexaminer's hand, and improves the repeatability of the of themonofilament stimulus application.

The new device includes any of the known monofilament diameter sizes, ornew diameter sizes, and lengths for the monofilament member. Nylon hasbeen determined optional for its elastic properties, but other suitablematerials may become available as determined in instrument testing, andthe monofilament in this device is not limited to nylon. Today the mostfrequently used diameters for force of application in testing are thosediameters sizes that at 38 mm in length from the point they leave thehandle produce forces in the order of 0.68 mg, 200 mg, 2 gm, 4 gm, 10gm, and 300 gms. The monofilaments are bent against skin surface todeliver stimulus force/pressure (force per unit area) to the subject.

In the most frequently used test protocol, each monofilament of a givendiameter size used in the test is applied, first in an area that thesubject can detect the monofilament as a reference. Then with thesubject's eyes averted, the area of suspected abnormality is tested bythe examiner applying the monofilament in a perpendicular fashion to theskin in 1.5 seconds, bending the monofilament, holding the monofilamentfor 1.5 seconds, and then lifting in 1.5 seconds, in a smoothapplication. If the patient responds with a “yes” or other affirmativeresponse, the cutaneous sensory detection threshold is recorded as beingthat level. If a subject does not respond in an area, then progressivelyheavier monofilaments are tried until either the subject detects one, orit is established the subject does not respond to any of themonofilaments used in a test set. Other protocols are possible,particularly additional protocols for one and two point discriminationtesting.

FIG. 2B shows my new device handle 15 with several devices nestedtogether where the new device handle design with the handle curve 17 andextension 19 protects the given size monofilament 21 from anotheradjacent handle. The curve and extension prevent one device when groupedor nested from being sheared off by its neighbor monofilament devicehandle. The curve and extension device handle design allows themonofilament devices to be secured together in a small box or case.Screen and monitoring sets today for testing patients require only fiveor six monofilament diameter sizes. These devices can be assembledadjacently in a small box for coat-pocket, tabletop, or other form ofdisplay and availability. With the original straight rod design, boxescontaining monofilament devices were frequently were knocked off of anexamination table. The lid would break or just open, and themonofilaments would then be scattered over the floor in manyorientations, damaging several that had to be replaced. The deviceswhile nested can be secured in the case with Velcro or other means forsafely securing them in the box in the event it is dropped, and the lidopens.

FIG. 3A shows the new device handle 15 and in one embodiment an optionaladaptor connector attachment 31 for two or more devices to be usedtogether for two-point testing. For two-point discrimination testing, 5and 10 grams of force levels have been suggested as an optimal startingpoint for controlled force of application. The monofilament 21 in my newdevice can be cut off at lengths to apply these relatively heavy gramforce levels. The elastic properties of the monofilament enables themonofilament to provide the same force of application for more than onedevice, thus providing force control that is missing in two-pointtesting devices.

FIG. 3B shows a close up of the connector attachment 31. The connectorin the example can hold two device handles together for concurrentapplication of two of the given size monofilament as is needed fortwo-point discrimination testing. Other variations in the connectorattachment can allow connection of more than two handles, if needed.

FIG. 4A shows my new device in the preferred embodiment, withreplacement disk 33. The disks are pre-embedded with the monofilament21, of a given size, and attached to the terminal end of the handle 15extension 19 and curve 17 and by an attachment means. The disks in thisembodiment are adhesive backed on their flat side to fit and attach ontothe end of the curve extension. These disks and monofilaments can besealed in packages and made available in clean or sterile packages. Evenif the device is made as in claim 1, the disk can be used to quicklyreplace a damaged monofilament. If the disks of devices becomedislodged, they can be secured again on the forward end of the curveextension 19 by self-stick adhesive backed tape available for thispurpose from the group of available adhesives and sticky backed tapes.

Replacement monofilaments are made available in disks pre-embedded withmonofilaments in the variety of sizes and test kits required incutaneous sensory detection threshold testing of light touch to deeppressure. Replacement monofilaments made available in disks pre-embeddedwith monofilaments can be disposable if needed, in the variety of sizesrequired in cutaneous sensory testing. Replacement disks can be madeavailable with two or a plurality of controlled force of applicationmonofilament stimulations. The replacement disks can be sealed and madeavailable in clean or sterile packages. The elastic properties of thenylon or similar material can provide controlled force of applicationfor replacement disks of more than one stimulus not attainable in otherconventional instruments used for this purpose.

FIG. 4B shows two alternative disk replacements with variation inmonofilament stimulus of two 35 or three 37 stimuli. Other alternativesare made possible by the controlled force of application provided by thenylon or similar elastic material that is not attainable in the designof other rigid probe conventional instruments used for this purpose.

FIG. 4C shows the new device handle 15 and an alternative means forsecuring the disk at the end the curve extension when the disks need tobe interchanged. A connector clip 39 is mounted to the second end of thehandle at the terminal end of the extension 19 and curve 17 and securedthrough a hole 41, in the handle at the end of the curve extension 19allowing the disk to slide into and out of position on the handle.Interchanging disks are necessary for placing types of monofilamentstimuli on one handle, without wasting handles or usable disks. Onecould also use more than one handle with pre-embedded disks with thedesired monofilament stimuli.

FIG. 4D shows close up of alternative clip embodiment 39. The clip goesthrough the hole that has been drilled for this purpose in the secondend of the handle. The disks can slide in and out of the clipindefinitely.

FIG. 4E shows the new device handle 15 and replacement disks can benested when performing a test on a subject, or included in a storagecase, without injury from adjacent monofilaments. On the monofilament 21second end of the handle extension 19 curve 17 and of the handle thedisk 33 also helps prevent one monofilament from being damaged by aneighboring handle. The disk 33 additionally helps keep the handle frombeing laid down on the monofilament. In the preferred embodiment, thedisk 33 is made of hard silicone rubber, and can serve as a bufferagainst the other device handles, and give the embedded monofilament aslight flexibility where it leaves to handle, decreasing the stress onthe monofilament at this vulnerable point.

FIG. 5A shows an example of an adaptor attachment 43, with a hole 45 tofit the device handle and a hole 47 to fit and connect thelight-emitting source 49 (represented by circled L) from the availablegroup of light-emitting sources. The new handle device design, with orwithout disk attachment, allows light to be attached to the testingdevice as needed.

FIG. 5B shows, in the preferred embodiment, the assembly of my newdevice, with removable or replaceable disk 33 with embedded monofilament21 as attached to the second end of the extension 19 and curve 17 of thehandle 15 second end, with mark 29 on the handle 15 for the examiner'sindex finger to hold the device, and adaptor attachment 43, for a smallconventional battery powered light 51 or similar from the group ofavailable light sources. Clear silicone rubber is available for thedisk, clear molded plastic for the adaptor, and clear acrylic plasticsuch as Lucite for the handle in this embodiment, but other clearmaterials also have light-emitting properties, and can be used for thisdesign.

FIG. 6 shows the new device applied to a subject's hand, and how, in thepreferred embodiment, the new device bends emitted light through thehandle 15 and is bent by the curve 17 and extension 19 through disk 33over the monofilament member 21 monofilament stimulus tip 23 and skinarea 53 and test site. The light serves to illuminate the monofilamentstimulus tip especially where applied to the skin area, improves theaccuracy of a cutaneous sensory test, and makes the test possible in lowlight, or no light conditions.

In my new device the optional addition of light assures the monofilamentis as visible as needed during testing to assure accurate application.If applied correctly using good testing procedure, the slippage of themonofilament is not an issue so long as the application can be seen bythe examiner and confirmed to be correct. It is important for theexaminer to be able to clearly see the approach and application of thetest stimulus to assure that correct delivery of force of applicationhas been given. The transmitted light provided by the new device has thepotential to improve test accuracy, given the commonality of shadowsproduced by external light sources, and less than optimal ambient lightconditions during use of cutaneous sensory detection and other hand-helddevices.

The option of the light to transmit through the device handle avoids theexaminer inadvertently heating the area being tested under a lamp orother hot light and thereby increasing the skin surface temperature atthe area being tested and potentially changing the subject's cutaneousthreshold detection level or the stiffness of the monofilament stimulus.The curve in one continuous unit handle allows cool light transmissionbecause of the physical properties of the plastic that bends the light.Clear plastic Lucite and any other material with similar properties isavailable in handle materials for this design. The embodiment of a lightattachment in the new device allows patient testing or monitoring ofpatients at night.

6. Conclusion, Ramifications, and Scope of Invention

The diameter width of rod handle in my design can be varied, but ifsmaller than 6.35 mm diameter does not serve to protect the monofilamentas well as the preferred embodiment. While a square rod helps keep thehandle from rotating; round rod handle can be used in an alternative.Round, oval, or any other shape diameter material can be used for thehandle equally as well as the square in the embodiment in examplesshown, so long as the curve and extension are included with the handle,and attachments are made to correspond with the alternative diametershape.

Handle material can be made of Lucite or any other synthetic materialbut is not limited to these except insofar as the light attachmentembodiment. Other rigid or relative rigid synthetic materials can beused for handles in claims 1 and 2 of the current device. With newtechnology it is possible there will become available a material thathas superior light-transmitting properties to acrylic plastic, and it isanticipated that similar materials if they become available would bemore ideal for the transmission of light. Light can be from manyalternative sources, including glow-in-the-dark, chemical, laser,digital, and various electronically generated from the group of lightemitting sources.

Disk material can be made of clear rubber silicone, Lucite plastic, orany other synthetic material but is not limited to these except insofaras being clear for the light attachment embodiment. Other rigid orrelative rigid synthetic materials can be used for disks in the currentdevice.

While the cutaneous sensory test is aimed at testing peripheral nervefunction, its use is not limited to testing peripheral nerves ofsubjects. It can also be used in patients with higher and more centralnervous system abnormality such as stroke and spinal cord injuries, aswell as for those with congenital absence of nerve function, diseasesand trauma.

The reader will see that the new device provides a highly reliable,lightweight, economical device to be used by persons who do cutaneoussensory detection testing. With respect to various embodiments, certainaspects of this invention have been described in detail. It will beapparent that other modifications can be made within the scope of thisinvention, and my invention should not be determined by, or limited to,the embodiments in the drawings and claims illustrated. It is notintended to limit my invention to the exact details shown above exceptas examples of embodiments, and insofar as they are defined in theclaims, particularly the attachment for light transmission that can beapplied to any cutaneous sensory testing devices. The attachmentconnector can be adapted to be suitable to a wide range of lightemitting sources, for the described, or other cutaneous sensory tests.

If the curve addition to the original straight Semmes-Weinstein designhandle is considered obvious, at the time of the current application,the curve better protecting the monofilament, allowing the handle rodsto be nested, and options for more than one concurrent stimulus have notbeen previously incorporated into any device design for clear plasticrod handles by any manufacturer, or patent, thus does not seem to havebeen obvious to them. If the light attachment is considered obvious, thenylon monofilament test was first created in the 1950's, and in practiceor in search at the time of application, I have not been able to findany previous utilization of the light transmission properties of Luciteand other acrylic plastics applied to cutaneous sensory testing devices.

1. A device for testing human or animal cutaneous sensory detectionconsisting of: a) a handle of plastic or similar material having a firstend and a second end, said first end to be held by an examiner, saidsecond end bent into a continuous curve with an extension and a means tohold a monofilament member test stimulus in a position perpendicular tothe length of said handle b) a handle means for securing saidmonofilament member of a selected force of application for testapplication c) a first protective means provided by the curve and theextension of said handle for improving protection of said monofilamentmember from damage when said device is used d) a second protective meansprovided by said curve and said extension of said handle for protectingsaid monofilament member whereby two or a plurality of said device canbe nested together without injury to said monofilament member e) anoptional connection attachment to said handle thereby providing a meansfor connecting said device to another f) a connection means forproviding said monofilament member to be individually, concurrently, orsequentially applied g) a mark or finger rest in the preferredembodiment, on said handle on the side opposite said monofilament memberat a given distance from said monofilament member for an index finger ofsaid examiner to be placed on said handle h) a consistent means forimproving controlled application of said monofilament member and furtherprotecting said monofilament member from damage in use and applicationfrom the hand of said examiner whereby the monofilament testing deviceis improved, better protected from damage to said monofilament member,more functional, and thereby more practical for use.
 2. As in claim 1and further including: a) a monofilament replacement object into whichone said monofilament member or the plurality thereof has been secured,and means for said monofilament member to be attached to the handle andinterchanged during testing of cutaneous sensory detection b) amonofilament replacement object, in the preferred embodiment, a disk,having a circumference and two sides, said disk flat on one side bywhich said disk has a means for being attached to the terminal end ofsaid curve of said handle, and can be attached to and detached from saidcurve at said second end, said disk on its other side thereof having acenter into which one said monofilament member or said plurality thereofhas been secured c) a buffer protective means provided by said diskaddition to said curve and said extension of said handle for protectingsaid monofilament member whereby a plurality of said device can benested together without injury to said monofilament member whereby saidmonofilament testing device is simple in design but more versatile inthat said monofilament member of predetermined size, shape, number, andforce of application can be replaced or interchanged, and appliedindividually, concurrently, and sequentially with repeatable force ofapplication.
 3. A device for testing human or animal cutaneous sensorydetection and connection means to a known light-emitting sourceconsisting of: a) a handle, or a plurality thereof, and connection meansto the light-emitting source, whereby the light travels through saidhandle, or a portion thereof, to illuminate a testing stimulus. b) ahandle, or said plurality thereof, and in one embodiment, an adaptor forconnection to said light-emitting source, said light illuminatingthrough said handle, and bent by said curve of said handle, toilluminate said monofilament member and a monofilament application tipthereof, said light emitting source selected from the group consistingof light emitting devices c) a handle, or said plurality thereof, and,in a preferred embodiment, the adaptor for connection to saidlight-emitting source, said light illuminating through said handle, andbent by said curve of said handle, and illuminating through said disk,to illuminate said monofilament member, and said monofilamentapplication tip, said light emitting source selected from said groupconsisting of light emitting devices d) a connection means fortransmitting light to, and illuminating, said monofilament member, andsaid monofilament application tip, or the plurality thereof e) a firstillumination means for providing light to a skin area, or a test site,during cutaneous sensory testing f) a second illumination means forproviding improved examiner visualization of said monofilament memberand said monofilament application tip, and thereby improved accuracy ofsaid device application whereby the cutaneous sensory detection devicetest stimulus can be seen by the examiner when applied in a variety oftest conditions wherein shadow and limited light may otherwise affectthe application accuracy of the intended test.